In conducting certain testing on bodily fluids such as blood, it is necessary to analyze the time that it takes the specimen to coagulate under certain specified conditions. In such a testing apparatus, it is common practice to use disposable sample containers, typically called cuvettes. When the specimen is placed in the cuvette, it is necessary to also place a small magnetic stirring rod in the cuvette to provide agitation to the specimen necessary to cause the coagulation. Because of the small size of the cuvettes and because of a need to not contaminate the side surfaces of the cuvette with fingerprints and the like when a photo-optical technique is being used for analyzing the coagulation progress, it is desirable to provide a cuvette holder which retains the cuvette in fixed spatial relationship to an optical path through the holder provided by apertures in the holder sides. It is also desirable to provide a cuvette holder having an impeller with a magnetic bar mounted on the impeller, so that the magnetic field induced by rotation of the impeller can cause a magnetic stirring rod contained within the cuvette to rotate in a complementary fashion.
A clinical calorimeter is an instrument which employs color filters, a light source, a sample holder, typically either a holder for interchangeable cuvettes or a flow cell, and a photo detector. In an aspirating system, a controlled vacuum source is used to draw the sample under test into a flow cell aligned with the light path defined by the light source and the photo detector. Measurements of the absorbance or transmission of the light by the sample are made and used to determine quantitatively such analytes as glucose, cholesterol, enzymes, etc. The temperature of the samples is carefully controlled. Because the clinical calorimeter aspirates the sample from the cuvette, the clinical calorimeter is not provided with means to agitate the sample.
A coagulation meter as is generally known in the prior art has a light source, a photo detector, a timer and a stirring means to determine the level of clotting agents in a serum sample. The reaction cuvette used is a vial containing a stir bar, which is magnetically coupled with a rotating magnetic source located in the coagulation meter. By knowing the time necessary for a clot to form on the stir bar and the temperature at which the test is conducted, the level of clotting agents present in a serum sample may be determined.
It is a desirable yet unachieved goal of the prior art to provide a cuvette holder which allows a clinical calorimeter to perform the function of the coagulation meter without sacrificing the advantages of the existing features.